This invention relates to phytosterols and pbytostanols, in particular to fatty acid esters of pbytosterols and/or phyostanols with a specified fatty acid composition. The invention further relates to methods for preparation of the phytosterol and/or phytostanol esters and their uses.
Since the 1950""s numerous studies in animals and humans have been reported, in which plant sterols (phytosterols) have caused significant reductions in serum cholesterol levels. Plant sterols Reduce serum cholesterol levels by reducing the absorption of cholesterol from the digestive tract. The mechanism or mechanisms by which this reduction in cholesterol absorption is taking place is not fully known.
Phytosterols are a group of compounds structurally very similar to cholesterol. The phyrosterols occurring most frequently in the nature are sitosterol, campesterol and stigmasterol. In all phytosterol preparations is sitosterol the main component. Most clinical and non-clinical studies have been conducted with so-called tall oil sterols, containing high amounts of sitosterol and some sitostanol. In the scientific literature such isterol blends are often referred to as sitosterol. Vegetable oils and fats are the main source of plant sterols in our diet. In vegetable oils a major part of the sterols exists as fatty acid esters.
In earlier study""s plant sterols have been used in poorly soluble, crystalline form with high daily intakes (up to 20-30 g/day). However, even when administered in relatively small doses (a few grams per day) and under optimum conditions, plant sterols reduce serum total and LDL-cholesterol levels.
In recent years plant sterol treatment of hypercholesterolemia has been refined by the use of the fully saturated form of sitosterol, sitostanol. Saturated phytosterols such as sitostanol and campestanol are present in our diet in small amounts. Daily intake of total stanols in the Finnish diet has been estimated to 30-80 mg/day. However, tall oil sterols (sterols from pine trees) contain 10-20% of plant stanols (sitostanol+campestanol). Phytostanols can also be produced by hydrogenation to remove the double bond in corresponding plant sterols.
Sitostanol is virtually unabsorbed and lowers the cholesterol content of mixed micelles more efficiently than sitosterol, thus showing an enhanced serum cholesterol lowering effect. Sugano et al. (Sugano M,. Morioka H. and Ikeda I. (1977) J. Nutr. 107, 2011-019) showed that sitostanol had a higher hypocholesterolermic activity than sitosterol in rats. Similar results were obtained with rabbits (Ikeda I,. Kawasaki A,. Samazima K. and Sugano M. (1981). J. Nutr. Sci. Vitaminol. 27, 243-251). In addition, sitostanol depressed the formation of aortic atheroma due to cholesterol feeding more than did sitosterol. Becker et al. (Becker M,. Staab D. and von Bergmann K. (1993) Journal of Pediatrics, 122, 292-296.) showed, that sitostanol was significantly more effective than sitosterol in reducing elevated levels of LDL cholesterol in children with severe familial hypercholesterolemia.
The solubility of free sterol and especially of free stanol in edible oils and fats is very low. E.g. less than 2% free sterols are dissolvable in oils and fats if water is present. This problem can be overcomed by esterifying the free sterols with fatty acid esters. Esters of plant sterols have been shown to be equal to corresponding free sterols in reducing cholesterol absorption in rat (Mattson F. H., Volpenheim R. H. and Erickson B. A., (1977), J. Nutr. 107,1139-46), while Mattson et al., (Mattson F. H., Grundy S. M. and Crouse J. R., (1982), Am. J. Clin. Nutr. 35, 697-700) found that free sterols were more effective in reducing cholesterol absorption in man.
During fat digestion dietary fat, sterol and/or stanol ester together with dietary cholesterol and its esters reach the intestinal oil phase (in intestinal emulsion), from which free stanols and sterols are released through lipolysis by enzymes like cholesterol esterase. The released free stanols and/or sterols compete with both dietary and biliary cholesterol for micellar solubility and lower the micellar phase concentration of cholesterol when present in lipid core fat material of the mixed micelles in high enough concentrations. Plant stanols like sitostanol is more effective in lowering micellar phase cholesterol than the corresponding sitosterol.
U.S. Pat. No. 3,751,569 (Erickson B. A.) describes clear cooking and salad oils having hypocholesterolemic properties. Into the liquid glyceride base oil is mixed 0.5-10 weight-% (as free sterol equivalent) of a sterol fatty acid ester. The cooking or salad oil was prepared by dissolving liquid glyceride base oil and plant sterols monocarboxylic acid in a mutual solvent and evaporating the solvent (hexane or diethyl ether). The fatty acid moiety was defined as a saturated monocarboxylic acid C1-12 or an unsaturated fatty acid with up to 24 carbon atoms. The sterol ester is added in an amount small enough to prevent precipitation at refrigerating temperatures. The solubility of different fatty acid esters of phytosterol in triolein are also presented, showing very low solubility for C14 and C16 saturated fatty acid phytosterol esters. This patent discloses the use of certain individual fatty acid esters of phytosterols added to the cooking or salad oil in relatively small amounts.
Saturated plant sterols have been shown to be more effective in reducing the absorption of cholesterol from the digestive tract and thus causing enhanced reduction of total and LDL serum cholesterol levels. Saturation of plant sterols to plant stanols further decreases their solubility in oils and fats. U.S. Pat. No. 5,502,045 (Miettinen et al.) discloses a method for producing fatty acid esters of sitostanol and the use of the substance for lowering high cholesterol levels. By esterifying the sitostanol blend with fatty acids from a vegetable oil such as rapeseed oil (LEAR) a fat-soluble stanol ester was obtained. Examples are given showing that up to 20% of the normally uses fat blend can be exchange with this sitostanol fatty acid ester blend based on low erucic acid rapeseed oil fatty acid esters. The incorporation of such fat-soluble stanol ester to food products like margarines and spreads provides a way to introduce the adequate daily amount of stanol for optimal reduction of the cholesterol absorption.
In several clinical studies these fat-soluble stanol esters have proven to be very effective in reducing the absorption of cholesterol from the digestive tract. The North Karelia stanol study was conducted to verify these findings in a 12 month large-scale randomised double-blind study (Miettinen T. A,. Puska P,. Gylling H,. Vanhanen H. and Vartianen E. (1995). N. Engl. J. Med. 333, 1308-1312). The results from this study show that a daily intake of 1.8-2.6 g of fat-soluble sitostanol ester (calculated as free stanol) administered in a margarine decreased the total cholesterol with 10% and the LDL-cholesterol with 14% compared to the reference group having a margarine without added fat-soluble stanol ester.
Stanol fatty acid esters with fatty acids based on commercially available high PUFA vegetable oils such as sunflower oil, corn oil, soybean oil, safflower oil, cottonseed oil or their blends will show too high texturizing properties in vegetable oils or their blends in order to be incorporated into foods like salad oils, cooking oils, easily pourable salad dressings, sauces and mayonnaises in amounts high enough for an adequate daily intake of stanols and sterols in order to obtain an optimal cholesterol lowering effect. This problem will be solved by the present invention.
Another problem in the prior art is the production of food products with very high contents of phytosterols in a form that could be added to a variety of food products in concentration high enough to supply by normal food intake the daily adequate amount of sterols and/or stanol for optimum effect on blood cholesterol levels. This was partly solved in the prior art by producing the fatty acid esters of the phytosterols and phytostanols. However, by using the sterol and/or stanol fatty acid esters according to the present invention even higher amounts of phytosterols and phytostanols can successfully be used in certain vegetable oil based food products like salads oils, cooking oils, easily pourable salad dressings, sauces and mayonnaises.
Furthermore, sterol and/or stanol esters according to the current invention can successfully be used in spread type of products such as margarines, low-fat spreads, spreadable cheeses, butter etc., wherever there is a desire to use conventional triglyccride hardstock and not utilise the texturizing properties obtainable from sterol esters and/or stanol Esters in the manufacturing of such products. One reason for such desire can be that utilising of sterol and/or stanol esters according to the present invention is technically not so demanding, making it more easy and feasible to produce such products with conventional production technology.
Capsules with free sterols and stanols suspended in safflower oil or mono-olein have been used as a mean for lowering elevated cholesterol levels. E.g. Denke (Denke (1995) Am. J. Clin. Nutr. 61, 392-396) fed 4 capsules/meal of free stanol suspended in safflower oil to men with moderate hypercholesterolemia as part of a cholesterol-lowering diet. The total daily intake of sitostanol was 3000 mg provided in 12 capsules. The sitostanol capsule regimen did not significantly reduce LDL cholesterol levels compared to the diet alone.
Due to the low solubility of free sitostanol in vegetable oils the use of capsules containing free sitostanol suspended in safflower oil does not ensure that the sitostanol is efficiently distributed into the fat phase of the food digest. This problem can be overcomed by using capsules based on sterol and/or stanol esters according to the present invention since these esters are liquid at body temperature and will easily be dissolved into the fat phase of the food digest. In addition no triglyceride fat or mono-olein is needed as a dispersing agent, making it possible to reduce the size or amount of capsules needed to supply the daily needed optimal amount of sterols and/or stanols.
The present invention is based on the finding that sterol and/or stanol fatty acid ester compositions, in which more than 50% of the fatty acid moieties comprises polyunsaturated fatty acids (PUFA), preferentially more than 60% and more preferred more than 65%, and less than 7% comprises saturated fatty acids (SAFA), preferentially less than 5%, show basically no texturizing properties and can thus be used in food products were such a texturizing effect is due to product quality or production technology reason undesirable or is wanted only to a very limited degree.
The invention is further based on the fact that stanol fatty acid esters based on rapeseed oil with a low content of saturated fatty acids and a high content of unsaturated fatty acids (mainly monounsaturated) give a DSC melting curve (FIG. 1), where all stanol fatty acid esters have co-crystallized. Thus, this blend of stanol fatty acid esters melts in one distinct melting peak measured with differential scanning calorimetry (DSC) after a directed crystallisation procedure. The DSC melting curve is obtained after melting the sample (about 8 mg) at 75xc2x0 C. for 10 minutes, after which the sample is crysallised by cooling at 10xc2x0 C./minute to xe2x88x9250xc2x0 C., where it is kept for five minutes. The melting curve is obtained by heating at 10xc2x0 C./minute to 70xc2x0 C.
Surprisingly it was found that stanol fatty acid esters based on vegetable high PUFA oils show a very different melting DSC curve (FIG. 2, stanol esters based on soybean fatty acids), where the stanol esters of polyunsaturated fatty acids seem to be melting (melting range from about xe2x88x925xc2x0 C. to about 25xc2x0 C.) in a distinct temperature range, different from the monounsaturated and saturated stanol fatty acid esters.
Based on the behaviour of the low erucic rapeseed oil based stanol fatty acid ester blend, showing only one uniform melting peak as measured by DSC, a similar PUFA stanol esters,directed crystallising and melting behaviour could be obtained, if the fatty acid composition of the stanol fatty acid esters is changed to markedly lower the content of saturated fatty acids and to somewhat increase the content of polyunsaturated fatty acids compared to natural high PUFA liquid vegetable oils.
High PUFA sterol and/or stanol esters can be produced by e.g. the method described in U.S. Pat. No. 5,502,045 (Miettinen et al.) by direct esterification of fatty acid alcohol esters obtained from high PUFA vegetable oils or their blends. Alternatively direct, preferably catalytic esterification methods or enzymatic esterification methods such as out-lined in EP-195 311 (Myojo et al.) can be used.
Sterol and/or stanol ester blends according to this invention can also be obtained by the method described in U.S. Pat. No. 5,502,045 by direct esterification of a fatty acid alcohol ester having appropriate fatty acid composition.
Furthermore, the fact that the PUFA fraction of stanol esters in high PUFA vegetable oil based stanol esters melts in a distinct temperature range indicates that stanol esters based on high PUFA vegetable oils can be subjected to fractionation in order to obtain stanol esters with decreased contents of saturated fatty acids and increased contents of polyunsaturated fatty acids in the fatty acid part.
It is obvious to persons skilled in the art that all fractionation processes of prior art including dry, wet, detergent and solvent fractionation processes or combinations of these can be used to obtain the desired compositions. Due to the high viscosity of stanol esters dry fractionation is not an optimal approach for achieving desired results. E.g. stanol fatty acid esters based on low erucic acid rapeseed oil show following viscosity values at specific temperatures: 728 cP at 48xc2x0 C., 80 cP at 100xc2x0 C. Corresponding values for low erucic acid rapeseed are 48.3 cP at 49.3xc2x0 C. and 8.4 cP at 100xc2x0 C. The problem with the high viscosity can however be overcomed by carrying out the fractionation step in a blend of sterol ester and/or stanol ester and a vegetable oil or a blend of vegetable oils. Preferably the used vegetable oil or vegetable oil blend is the one desired in the final food product. The vegetable oil markedly decreases the viscosity of the sterol and/or stanol ester vegetable oil blend, making the fractionation feasible with any commercially available dry fractionation process of prior art.
An other possibility is to utilise the excess of high PUFA alcohol esters present in the oily phase obtained after the esterification of high PUFA sterol and/or stanol ester according :to the method described in the U.S. Pat. No. 5,502,045 (Miettinen et al.). This high PUFA alcohol ester sterol and/or stanol ester mixture can as such be subjected to a fractionation step to remove higher melting sterol and/or stanol esters.
Saturation of a plant sterol blend to corresponding plant stanol blend causes marked differences in melting properties of corresponding sterol/stanol esters with the same fatty acid composition. E.g. vegetable oil based sterol ester with low erucic acid rapeseed oil fatty acids and corresponding stanol fatty acid ester showed the following amounts of solid fat contents (percent of total fat) at different temperatures as measured by NMR-technique:
Based on these data, it is obvious to persons skilled in the art that any blend of sterol and/or stanol fatty acid esters will show solid fat content values in the intermediate range of the sterol and stanol fatty acid esters with corresponding fatty acid compositions.
The present invention further makes it possible to incorporate increased amounts of plant sterols, plant stanols or their blends into specific foods, such as salad and cooking oil, easily pourable salad dressings, sauces and mayonnaises, where the content of sterol and/or stanol ester based on ordinary high PUFA fatty acid compositions would have to be reduced in order not to change the physical and sensor properties of the final product. It is evident from the data presented, that the present invention makes it easier to supply a daily adequate amount for optimal cholesterol reducing efficacy from such specific products, without having to compromise on the quality of the product.
Another area of potential use for sterol esters, stanol esters or their blends with a high PUFA and low SAFA fatty acid composition is capsules with totally liquid sterol and/or stanols esters at body temperature, rapidly dissolving into die fat phase of the food digest in the stomach. The use of sterol and/or stanol esters according to the present invention will overcome prior problems with capsules based on free sterols and/or stanols suspended in vegetable oils or mono-olein.
It is believed that the optimum cholesterol lowering effect is achieved, if the sterols, stanols or their blends are efficiently dissolved into the fat phase of the digesting food. It is assumed that the sterols and stanols need to be dissolved in the fat phase of the digesting food in order to have an efficient reducing effect on the cholesterol absorption. Furthermore, dietary cholesterol accounts for only about ⅓ of the total cholesterol amount entering the digestive tract daily. Biliary cholesterol is the main source of intestinal cholesterol.
In order to have an optimal cholesterol reducing effect from the use of plant sterols and stanols, they should be present in the digestive tract whenever food intake causes the gallbladder to contract. Therefore, the use of fat-soluble sterol and stanol esters incorporated into regular food products seems to be an optimal choice of delivering the sterols and/or stanols.
However, there are many occasions, when plant sterol and/or stanol enriched food products are not available. Therefore, the use of capsules, e.g. gelatine capsules, or tablets would be another possible approach for delivering the optimal daily dose at meals, making the sterol/stanol regimen available all the time. A sterol or stanol fatty acid esters capsule with a fatty acid composition according to the present invention would be totally melted at body temperature and dissolve fast in the fat-phase of the food digest. The efficient dissolving of sterol and/or stanol esters according to the present invention will be ensured without the use of additional dissolving lipid materials, since the sterol and/or stanol esters according to the present invention will be liquid at body temperate. In addition no triglyceride fat or mono-olein is needed as a dispersing agent, making it possible to reduce the size or amount of capsules needed to supply the daily needed optimal amount of sterols and/or stanols.
Clear cooking and salad oils with much higher plant sterol contents (sterol equivalent) than disclosed in the prior art can preferably be produced by using sterol esters according to the present invention. The clear cooking and salad oils disclosed in the prior art are based on the use of phytosterol esters based on individual saturated fatty acid moieties with less than 12 carbon atoms or individual unsaturated fatty acids with up to 24 carbon atoms. The limited amount of saturated fatty acids contained in the sterol and/or stanol esters according to the present invention is primarily based on the saturated fatty acids naturally contained in the parent high PUFA vegetable oil or vegetable oil blend, namely saturated fatty acids with more than 14 carbon atoms, The sterol and/or stanol fatty acid esters according to the present invention can be utilised in low-fat products and in products for consumers wishing to eat only small amounts of fat-containing foods. The stanol esters according to the invention can also be used in a somewhat increased amount compared to prior art. Therefore, by using sterol and/or stanol fatty acid esters according to the present invention the daily dosage needed for effective lowering of the cholesterol level can easily be accomplished.
The compositions according to the invention also have the obvious positive effect from a nutritional point of view as the fatty acid composition in the food product is changed to a lower content of saturated fatty acids and a higher content of unsaturated fatty acids. Based on the fact that the sterol and/or stanol part is unabsorbable also the amount of absorbable fat is reduced in the food products, since the sterol and/or stanol esters are replacing about an equal amount normal triglyceride fat.
The use of stanol fatty acid esters defined as in claim 1 or 2 is the preferred way of practising the present invention. The most preferably used stanols comprise sitostanol and optionally campestanol.
The term high PUFA vegetable oils is in this specification meant to be vegetable oils or vegetable oil blends containing more than 50% polyunsaturated fatty acids and at least 7% saturated fatty acids of the fatty acid composition. Typical high PUFA oils include sunflower oil, corn oil, soybean oil, safflower oil, cottonseed oil or their blends. The amount of saturated fatty acids in the fatty acid composition is about 7.5-49%, more typically about 8-25% and most typically about 10-20%.
By the term phytosterol is in this specification meant 4-desmethyl sterols, 4-monomethyl sterols, and 4,4-dimethyl sterols (triterpene alcohols) or their blends. By the term phytostanol is in this specification meant 4-desmetyl stanols, 4-monomethyl stanols and 4,4dimethyl stanols preferably obtained by hydrogenation of the corresponding phytosterol. Typical 4-desmethyl sterols are sitosterol, campesterol, stigmasterol, brassicasterol, 22-dehydrobrassicasterol, xcex945-avenasterol. Typical 4,4-dimethyl sterols are cycloartenol, 24-metylenecycloartanol and cyclobranol. Typical phytostanols are sitostanol, campestanol and their 24-epimers, cycloartanol and saturated forms obtained by saturation of triterpene alcohols (cycloartenol, 24-metylenecycloartanol and cyclobranol). By the terns phytosterols and phytostanol is in this specification further meant all possible, natural blends of 4-desmethyl sterol and stanols, 4-monomethyl sterols and stanols, 4,4-dimethyl sterols and stanols and mixtures of natural blends. By the terms phytosterols and phytostanols is in this specification further meant any individual 4-desmethyl sterol, 4-monomethyl sterol or 4,4-dimethyl sterol or their corresponding saturated forms.
The terms plant sterol and plant stanol are used in this specification as synonyms to phytosterol respectively phytostanol. Sterol and stanol shall also mean phytosterol respectively phytostanol.
Polyunsaturated fatty acids are here defined as fatty acids containing 2 or more double bonds. Preferentially the double bonds should have cis configuration, but one or more double bonds could be in trans configuration. It is known that many commercially available vegetable oils due to termal isomerisation in the deodorisation process contain % levels of polyunsaturated fatty acids containing one or more double bond with trans configuration. In addition the double bonds can be either so-called methylene interrupted or conjugated. Typical vegetable oil derived polyunsaturated fatty acids are linoleic, linolenic and xcex3-linolenic acid, but also polyunsaturated fatty acids from fish oils such as eicosapentaenoic and docosahexaenoic acid can be utilised.
By the term saturated fatty acids is meant fatty acids with 4-24 carbon atoms not having any double bonds, thereby including both straight chain and branched fatty acids.
By the term high PUFA sterol and/or stanol esters is meant sterol and/or stanol esters produced preferentially with fatty acids from high PUFA vegetable oils, but also fish oil derived polyunsaturated fatty acids or blends of vegetable and fish oil derived polyunsaturated fatty acids can be used.
The sterol esters, stanol esters or their blends can preferably be produced by the method outlined in U.S. Pat. No. 5,502,045 (Miettinen et al.) using a fatty acid alcohol ester with a specified fatty acid composition according to the present invention. The fatty acid alcohol esters can be produced by any process known in the art, such as solvent or detergent fractionation of alcohol fatty acid esters obtained from a high PUFA liquid vegetable oil or blends of high PUFA oils. Corresponding blends of fatty acid alcohol esters can also be obtained by distillation procedures under reduced pressure. Such distillation procedures can preferentially be used to remove saturated fatty acids with 16 or less carbon atoms. Fatty acid alcohol esters with the defined fatty acid compositions can also be obtained by alcoholysis of vegetable oils or oil blends with reduced contents of saturated fatty acids, obtained e.g. according to the U.S. Pat. No. 5,670,348 (William et al.).
The sterol and/or stanol esters can also be produced by direct, preferably catalytic esterification methods between free fatty acids or fatty acid blends of said composition and the sterol and/or stanol. In addition sterol and/or stanol esters can also be produced by enzymatic esterification e.g. as out-lined in EP-195 311.
In addition blends of polyunsaturated fatty acids can be used for obtaining sterol and/or stanol esters with the defined composition.
Stanol esters and/or sterol esters with the, defined fatty acid compositions can further be obtained by commercially applied fractionation processes, such as dry, detergent and wet-type fractionation of stanol and/or sterol fatty acid esters obtained by esterification of high PUFA fatty acids derived from e.g. vegetable oil or oil blends by methods based on e.g. the transesterification process outlined in U.S. Pat. No. 5,502,045, any direct preferably catalytic esterification process or by the use of an enzymatic esterification process e.g. as out-lined in EP 195 311. Especially fractionation from solvents can be used for preparing desired sterol and/or stanol ester compositions. When using enzymatic esterification processes such as out-lined in EP 195 311 the fractionation can preferably be carried out directly in the reaction solvent used in the esterification process after removing the enzyme and possible water phase.
In a preferred embodiment vegetable oils containing desired sterol and/or stanol fatty acid esters can be obtained by dissolving 15-50 weight-% (preferentially 15-25%) of sterol and/or stanol fatty acid esters obtained by an esterification process such as that disclosed in U.S. Pat. No. 5,502,045 by using a high PUFA vegetable oil or a mixture of high PUFA vegetable oils as a source for the fatty acids. The so obtained sterol and/or stanol esters vegetable oil blend is heated and mixed to totally dissolve the sterol and/or stanol esters after which conventional winterising or any fractionation process of prior art is carried out. E.g. a winterising/batch dry fractionation process can be carried out at 5-20xc2x0 C. depending on the type of sterol ester and/or stanol ester used. Then the solid part of the sterol or stanol ester is removed e.g. by vacuum filtering and the liquid part containing the sterol ester, stanol ester or their blend with the desired fatty acid composition according to the invention is subjected to normal deodorising before use in the manufacturing of the end product or bottled to be used as cooking or salad oil. It is obvious to those skilled in the art that any type of fractionation process in addition to the winterising or batch dry fractionation processes can be utilised for crystallising and removing sterol and/or stanol fatty acid esters with higher melting points, i.e. sterol and/or stanol fatty acid esters based on saturated fatty acids namely.
In an other preferred embodiment stanol esters and/or sterol esters with the defined fatty acid compositions can further be obtained by utilising the excess of fatty acid methyl ester of the high PUFA sterol and/or stanol ester blend obtained after the direct esterification disclosed in U.S. Pat. No. 5,502,045 (Miettinen et al.). After the drying step the sterol and/or stanol ester fatty acid alcohol ester mixture is cooled to 10-25xc2x0 C., depending on the composition of the sterol and/or stanol ester produced, and the higher melting components are allowed to crystallise for 4-6 hours. Optionally additional fatty acid alcohol ester is added to facilitate the fractionation process. Any fatty acid alcohol ester may be used, but the use of high PUFA alcohol ester is preferred. After filtration the clear oily phase is preferably deodorised to remove the excess fatty acid alcohol esters and to obtain a tasteless sterol and/or stanol ester.
The sterol and/or stanol esters obtained as such can preferably be mixed into oil blends prior to the final deodorising step of the fat blend to be used in the production of the final food product. Alternatively the sterol and/or stanol ester can be deodorised as such and used as such e.g. in the production of capsules. Furthermore the deodorised sterol and/or stanol esters according to the present invention can be dissolved in the vegetable oil or vegetable oil blend to be used as such as e.g. salad or cooking oil or to be used in the production of specific food, especially low-fat food products, salad dressings, mayonnaises, sauces or any fat-containing food product, where a sterol and/or stanol ester with no or limited texturing properties for product quality or production technology reasons are desirable. In another embodiment the oil can be added to the mixture already before the fractionation to facilitate the procedure.
Vegetable oils containing desired sterol esters, stanol esters or their blends can further be produced by carrying out the esterification in.the oil blend in a similar way as described in GB patent 1 405 346 (Baltes et al.). The obtained totally interesterified oil is subjected to a subsequent fractination step such as a winterising step to obtain a vegetable oil containing desired amounts of sterol esters, stanol esters or their blends. Alternatively, an esterified vegetable oil sterol and/or stanol ester stock blend with a high content of sterol and/or stanol ester (20-90 weight-% sterol and/or stanol ester) can be produced by the same approach. The obtained triglyceride sterol and/or stanol ester blend can then be blended in proportions needed to obtain the desired content of sterol esters, stanol esters or their blends with the unesterified vegetable oil or vegetable oil blend to be used in the final product before the winterisation or fractionation process to remove mainly higher melting sterol and/or stanol esters with saturated fatty acids, Furthermore, the fractionation process can be carried out after the esterification step, utilising the excess of fatty acid alcohol esters. Optionally additional fatty acid alcohol ester is added to facilitate the fractionation process.
In addition sterol and/or stanol ester compositions according to the invention can be produced utilising xe2x80x9cfatty acid starting materialsxe2x80x9d such as fatty acids, fatty acids alcohol esters or oils obtained by processes including e.g. utilising of micro-organisms, enzymes or new breedings of oil producing plants.